Design and fabrication of the terahertz antenna structures based on micro-nano optics

The terahertz imaging is mostly detected by the pyroelectric method which put forward high requirements on the average terahertz power generated by terahertz source. According to recent studies, a terahertz imaging method based on quantum tunneling is proposed. In this method, the generated photoelectron is related to the peak electric field of the incoming terahertz radiation. By designing the resonant properties of the structured metallic layer or layers in the terahertz range, narrowband and broadband detection of terahertz radiation is possible. Also, by engineering the field enhancement properties of the structured metallic layer the sensitivity range of the terahertz detector may be changed. In this paper, the terahertz antenna structure is designed by COMSOL and CST for a certain terahertz frequency band (0.14 THz). The optimal structure with structure period is about 200 μm is obtained through modeling and simulation. Meanwhile, other structure parameters such as line width and gap width (100 nm) are obtained. The simulation results show that the local electric field strength can reach 10⁸ V/m. Combined with the simulation results and the actual preparation capability, the terahertz antenna is prepared by nanoimprint lithography and Ion Beam Etching (IBE). Here, the preparation process of terahertz antenna is briefly introduced and preliminary preparation results are given.